1. Field of the Invention
This invention relates generally to tape cassettes, and more particularly, is directed to improvements in tape cassettes for use in a recording and/or reproducing apparatus, such as video tape recorders and the like. Still more particularly, the invention relates to an improved coil spring with an enhanced area of contact with a latch element for releasing a lid structure of the cassette.
Still more particularly, this invention relates to an improved coil spring having a leg portion bent to improve its effective surface contact with a mating surface on a lid latch element and to an enhanced spring contact abutment area on the lid latch element.
2. Description of the Prior Art
A tape cassette for use in a conventional video tape recorder (hereinafter referred to as a VTR) is provided with an opening extending along one side of the cassette housing and with a cutout in the bottom of the housing communicating with such opening. The magnetic tape wound on reels rotatable within the cassette housing is guided in a run extending across the opening and, when the tape cassette is loaded in a cassette holder of the VTR, tape loading pins mounted on a loading ring are inserted into the cutout of the cassette housing in back of such tape run. Upon rotation of the loading ring, the tape loading pins engage the tape in the run between the reels, withdraw the tape from the cassette housing and wrap the withdrawn tape around the peripheral surface of a guide drum of the VTR. The conventional tape cassette is usually provided with a lid which is movable on the cassette housing between a closed position covering the opening of the housing and an open position to which the lid is moved when the cassette is placed in the cassette holder and in which the tape run extending across the housing opening is fully exposed.
Although the lid of the foregoing conventional tape cassette, when in its closed position, is intended to prevent accidental damage to the run of the tape extending across the opening of the cassette housing, such lid, even when in its closed position only covers the outer surface of the tape run. Therefore, dust or the like may adhere to the back surface of the tape run which is exposed through the cutout in the bottom of the cassette housing even when the lid is in its closed position. As a result, dropouts may occur in the recording and reproducing of signals on the tape.
In order to provide increased protection for the tape in a cassette of the described type, it has been proposed, for example, in U.S. Pat. No. 4,418,373, issued Nov. 29, 1983, and having a common assignee herewith, to provide the cassette housing with a lid structure which, when in a closed position, that is, when the cassette is not in use, completely encloses the tape run extending between the reels across an opening of the cassette housing. Such lid structure is urged to its closed position by a coil spring associated therewith, and which gives rise to difficulties in assembling the tape cassette.
Other examples of tape cassettes are shown in U.S. Pat. Nos. 4,449,677 and 4,482,104, each of which is assigned to the assignee of the instant invention.
In addition, in the parent application, it was proposed to provide a tape cassette, as aforesaid, having a coil spring by which a lid structure of the cassette housing is urged to a closed position and in which an arrangement is provided for facilitating the position of such coil spring during the assembly of the various parts of the cassette. In the embodiment there shown, however, the angularly disposed leg portion of the coil spring was in the form of an elongated wire leg which provided limited contact area between the outer surface of the generally cylindrical wire and the irregular, but rounded mating receiving surface on the lid latch element. Because the free end of the elongated leg portion of the coil spring was located remote from a main spring anchor for the coil portion of the spring, lateral movement was possible between the walls of a space provided for contact with the leg portion of the coil spring with a rounded abutment on the housing of the latch element. Such structure sometime permitted, such as after an impact on the cassette from dropping or the like, the relatively free end of a coil spring to move laterally out of engagement with the latch element, inhibiting the latch release function for the lid.
Accordingly, it is a primary object of this invention to improve the contact between the leg portion of the coil spring and the rounded abutment spring-receiving end of the latch element for the lid, in a tape cassette of the type described.